• Microbiology and Biotechnology Letters
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• v.51 no.1
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• pp.10-17
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• 2023

Dairy products are extensively used as carriers of probiotic strains that have potential health benefits. Assessment of the viability of probiotic strains during manufacturing is important to ensure that products meet recommended levels. Hence, the method for accurately quantifying lactic acid bacteria (LAB) in probiotic or dairy products is required. The present study aims to examine the performance of de-Man Rogosa Sharpe (MRS), plate count agar with bromocresol purple (PCA with BCP), and glucose blood liver (BL) agars recommended in the Korea Food Code guidelines for counting LAB. Analysis of the performance of culture media containing 19 lactic acid bacterial species commonly encountered in probiotic and dairy products showed no statistically significant difference between 18 reference strains and three culture media (p > 0.01). Furthermore, the suitability of three culture media was verified for the quantitative assessment of LAB in 25 probiotic and dairy products. The number of LAB in three culture media was determined to be more than 10⁷ colony-forming unit (CFU)/ml for fermented milk products and 10⁸ CFU/ml for condensed fermented milk and probiotic products, indicating that they all satisfied the Korea Food Code guidelines. Moreover, there was no statistically significant difference in the amount of LAB counted in all three culture media, suggesting that they can be used to isolate or enumerate LAB in commercial products. Finally, three culture media will be useful for isolating and enumerating LAB from fermented foods as well as gut microflora.

• Food Science of Animal Resources
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• v.29 no.4
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• pp.423-429
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• 2009

The objective of this study was to investigate the potential of the application of lactic acid bacteria (LAB) from kimchi as a starter culture in the production of fermented sausages. To achieve this, a submerged model medium that contained LAB as part of a complex system of kimchi (0.5, 1.0, 1.0, 3.0, and 5.0%) and lyophilized kimchi powder (0.2 and 0.5%) was fermented for 120 h. During the fermentation period, the growth of total viable organisms and LAB, and the changes in the pH and the titratable acidity, were investigated. The initial LAB counts ranged from 6.4 to 7.7 Log CFU/mL for the kimchi media, and from 6.9 to 6.9 Log CFU/mL for the kimchi powder media. In all the kimchi batches, the LAB increased logarithmically, and the highest LAB counts (around 9 Log CFU/mL) were reached in 24 h. An evident lag phase of the LAB was observed in the kimchi powder samples and reached 8.8 Log CFU/mL in 8 h. The decrease in the pH and the formation of lactic acid were rapid in the kimchi batches, and reached pH values of 3.4-3.5 in 12 h. With these results, the LAB that was integrated with the addition of kimchi or kimchi powder demonstrated its potential utility as a substitute for starter culture.

• Archives of Pharmacal Research
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• v.29 no.9
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• pp.735-740
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• 2006

Lactic acid bacteria (LAB) quickly attenuate or are killed during the freeze-drying process and storage. The effect of some natural polysaccharides, which are known as potent antitumor and immunomodulating substances, on the viability of the LAB, Lactobacillus acidophilus and Bifidobacterium breve, on freeze-drying and storage were investigated. Among the polysaccharides tested, red ginseng polysaccharide (RGP) and chitosan significantly inhibited the cell death of the LAB during freeze-drying, and fucoidan and RGP most potently protected the cell death of the LAB during storage. The stabilities of the LAB on the addition of RGP and fucoidan were comparable to that of skimmed milk. However, white ginseng polysaccharide (WGP) did not promote storage stability. When 5% skimmed milk/5% RGP treated LAB were freeze-dried and stored, their viabilities were found to be significantly higher those treated with 5% or 10% RGP. The stabilizing effect of 5% RGP/5% skimmed milk during LAB freeze-drying and storage stability was comparable to that of treatment with 10% skimmed milk. Based on these findings, we believe that RGP beneficially improves the stability of LAB during the freeze-dry process and storage.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.10a
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• pp.319-323
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• 2005

Lactic acid bacteria are dominant microflora in many kinds of fermented foods. In this study, dominant microflora, especially lactic acid bacteria were isolated from salted sea food, and we determined physiological characteristics, and assayed specific property such as bacteriocin activity. The population of lactic acid bacteria as well as aerobic mesophilic counts was at the level of $10^7$ cfu /g. Total 17 strains of LAB were isolated from salted sea food sample. The phenotypic characteristics of these strains were determined followed by Bergey's Manual. And genotypic and bacteriocin activity were tested by Schillinger and $L{\ddot{u}}cke^{(7)}$.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1790-1797
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• 2002

Lactic acid bacteria were isolated from piglets and chicken and characterized. Lactic acid bacteria showing resistance to low pH and bile, adhesion to intestinal epithelium cells, and the inhibition of Escherichia coli and Salmonella spp. were identified as Lactobacillus acidophilus. L. acidophilus PF01 survived for 2 h in MRS broth adjusted to pH 2. L. acidophilus CF07 was less resistant than L. acidophilus PF01 to pH 2, but survived at pH 2.5 for 2 h. Both of isolates were able to grow in MRS broth containing 0.3% (w/v) bile, with L. acidophilus CF07 being more tolerant to bile than L. acidophilus PF01. L. acidophilus PF01 and CF07 adhered specifically to the duodenal and jejunal epithelium cells of piglet, and the cecal and duodenal epithelium cells of chicken, respectively. Both of isolates did not adhere to the epithelium cells of the various animal intestines from which they were isolated. When L. acidophilus was cultured with E. coli and Salmonella spp. in MRS broth, MRS broth containing 2% skim milk powder or modified tryptic soy broth at $37^{\circ}C$, L. acidophilus PF01 and CF07 inhibited the growths of E. coli K88 and K99, and S. enteritidis and S. typhimurium, respectively. Both of isolates were found to possess the essential characteristics of probiotic lactic acid bacteria for piglet and chicken.

• Microbiology and Biotechnology Letters
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• v.29 no.1
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• pp.1-11
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• 2001

Lactic acid bacteria (LAB) are widely used for various food fermentation. With the recent advances in modern biotechnology, a variety of bio-products with the high economic values have been produced using microorganisms. For molecular cloning and expression studies on the gene of interest, E. coli has been widely used mainly because vector systems are fully developed. Most plasmid vectors currently used for E, coli carry antibiotic-resistant markers. As it is generally believed that the antibiotic resistance markers are potentially transferred to other bacteria, application of the plasmid vectors carrying antibiotic resistance genes as selection markers should be avoided, especially for human consump-tion. By contrast, as LAB have some desirable traits such that the they are GRAS(generally recognized as safe), able to secrete gene products out of cell, and their low protease activities, they are regarded as an ideal organism for the genetic manipulation, including cloning and expression of homologous and heterologous genes. However, the vec-tor systems established for LAB are stil insufficient to over-produce gene products, stably, limiting the use of these organisms for industrial applications. For a past decade, the two popular plasmid vectors, pAM$\beta$1 of Streptococcus faecalis and pGK12 theB. subtilis-E. coli shuttle vector derived from pWV01 of Lactococcus lactis ssp. cremoris wg 2, were most widely used to construct efficient chimeric vectors to be stably maintained in many industrial strains of LAB. Currently, non-antibiotic markers such as nisin resistance($Nis^{r}$ ) are explored for selecting recombi-nant clone. In addition, a gene encoding S-layer protein, slp/A, on bacterial cell wall was successfully recombined with the proper LAB vectors LAB vectors for excretion of the heterologous gene product from LAB Many food-grade host vec-tor systems were successfully developed, which allowed stable integration of multiple plasmid copies in the vec-mosome of LAB. More recently, an integration vector system based on the site-specific integration apparatus of temperate lactococcal bacteriophage, containing the integrase gene(int) and phage attachment site(attP), was pub-lished. In conclusion, when various vector system, which are maintain stably and expressed strongly in LAB, are developed, lost of such food products as enzymes, pharmaceuticals, bioactive food ingredients for human consump-tion would be produced at a full scale in LAB.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.11
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• pp.1747-1755
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• 2018

Objective: Common reed (Phragmites communis Trin.) could potentially provide an alternative resource for silage; however, its silage quality is poor. The aim of this study was to investigate the factors in reed that contribute to poor quality and determine how the use of additives at ensiling could improve fermentation quality. Methods: In Experiment 1, we determined the chemical composition and the presence of indigenous lactic acid bacteria (LAB) in reed. We further examined fermentation quality of reed silage under conditions without additives (NA) and treated glucose (G), lactic acid bacteria (L), and their combination (G+L). In Experiment 2, silage of NA, and with an addition of cellulase and lactic acid bacteria (CL) were prepared from harvested reed. The harvested reeds were fertilized at nitrogen concentrations of 0, 4, 8, and $12g\;N/m^2$ and were harvested thrice within one year. Results: The indigenous LAB and fermentable carbohydrates are at extremely low concentrations in reed. Reed silage, to which we added G+L, provided the highest quality silage among treatments in Experiment 1. In Experiment 2, N fertilization had no negative effect on silage quality of reed. The harvest times decreased fermentable carbohydrate content in reed. The CL treatment provided a higher lactic acid content compared to the NA treatment. However, the quality of CL treated silage at the second and third harvests was significantly lower than at the first harvest, due to a reduction in carbohydrates caused by frequent harvesting. Conclusion: The causes of poor quality in reed silage are its lack of indigenous LAB and fermentable carbohydrates and its high moisture content. In addition, reed managed by frequent harvesting reduces carbohydrate content. Although the silage quality could be improved by adding CL, higher-quality silage could be prepared by adding fermentable carbohydrates, such as glucose (rather than adding cellulases).

• Microbiology and Biotechnology Letters
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• v.25 no.2
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• pp.229-234
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• 1997

Shizandra chinensis(SC) and Pinus regida(PR) showed antimicrobial activity against 3 strains(B-5, D-1, A-1) of lactic acid bacteria(LAB) isolated from kimchi among eight kinds of plant extracts such as Shizandra chinensis, Phellodendron amurense, ornus officinalis, Pinus regida, Allium tuberosum, Machilus thunbergii, Cyperus rotundus and Schizonepeta tenuifloia. The growth of LAB was inhibited apparently in modified MRS broth containing 1% Schizandra chinensis at $35^{\circ}C$. Pinus regida showed weaker inhibitory effect on the growth of isolated LAB than Shizandra chinensis. pH of SC added kimchi did not change greatly compare with control during 25 days of fermentation. Degree of titratable acidity change and ratio of reducing sugar utilization in control were more higher than in SC added kimchi during fermentation. Growth of total bacteria and lactic acid bacteria was inhibited about 1 to 2 $log_10$ cycle by addition of SC extracts during kimchi fermentation for 10 days at $10^{\circ}C$. Fermentation of kimchi was delaved about 5 to 7 days by addition of 1 or 2% of SC. extract, but sensory quality (falvor, taste and overall acceptability) of SC added kimchi was lower than that of control (p>0.05).

• Food Science and Biotechnology
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• v.17 no.4
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• pp.857-860
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• 2008

S-Adenosyl-L-methionine (SAM) is a bioactive material used in the treatment of depression, osteoarthritis, and liver disease. To obtain lactic acid bacteria (LAB) producing high concentrations of SAM, LAB were isolated from commercial kimchi and from prepared kimchi products that contained shrimp jeotgal (fermented salty seafood) or sand lance jeotgal or that were fermented at 5 or $10^{\circ}C$, respectively, when pH was 4.2 to 4.8 and titratable acidity 0.6 to 0.9. Among the 179 LAB strains isolated from the fermented kimchi products, the genus Leuconostoc produced the highest intracellular level of SAM (1.58 mM) and Lactobacillus produced the second highest level (up to 1.47 mM) in the strain culture. This is the first study to quantify SAM in LAB isolated from fermented kimchi prepared by a general kimchi recipe. Ultimately, the selected strains (Leuconostoc mesentroides subsp. mesenteroides/dextranicum KSK417, L. mesentroides subsp. mesenteroides/dextranicum KJM401, and Lactobacillus bifermentans QMW327) could be useful as starters to manufacture fermented foods containing high levels of SAM.

• Journal of fish pathology
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• v.23 no.3
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• pp.343-355
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• 2010

This study was conducted to investigate the dietary effects of lactic acid bacteria (LAB) supplementation on growth, hematological and immune responses of grey mullet, Mugil cephalus. Three replicate groups of grey mullet (body length, $62.8{\pm}1.04\;mm$ ; body weight, $3.2{\pm}0.13\;mg$) were fed the experimental diets with 0 (control), 1, 2.5 and 5,0 % of LAB for 3 months. Total body length growth rate was increased in 2.5 % supplementation group compared to control (P<0.05). No differences were observed in hematological parameters (hematocrit, hemoglobin, RBCs) and serum chemistry (calcium, magnesium, total protein, glucose, GOT and GPT). The antioxidant activity of grey mullet fed the 5.0 % LAB diets was significantly higher than that of other groups (P<0.05). Both intracellular superoxide anion production and lysozyme activity of kidney were higher in the 2.5 % LAB diet than in the control (P<0.05).